Stephens, a job counsellor who worked with teenagers and young people, was wanted on murder charges over the shooting of Robert Godwin Sr.

The 74-year-old former foundry worker and father of 10 was picking up aluminium cans on Sunday when he was gunned down in Cleveland.

The chilling video was posted on Facebook for three hours before it was taken down, drawing criticism of the social network and renewing questions about how responsibly it polices objectionable material.

At a Silicon Valley conference on Tuesday, Facebook chief executive Mark Zuckerberg briefly addressed the Cleveland case, saying Facebook has “a lot of work to do” and “we will keep doing all we can to prevent tragedies like this”.

Police would not speculate on what was behind the killing, but in the video and other footage he posted, Stephens talked about losing everything he had to gambling and having trouble with his girlfriend. He said he “just snapped”.

One of Mr Godwin’s daughters, Debbie Godwin, said she wished Stephens had been captured.

“I’m not happy he’s dead at all, not at all. If you did it, you have to face your crime,” she said.

An armour police vehicle drives through Fairmount park in Philadelphia

The break in the case came when police received a tip that Stephens’s car was in the McDonald’s car park in Erie, in the north-western corner of the state, about 100 miles east of Cleveland, authorities said.

The chase lasted two miles before Stephens took his own life, police said.

Facebook said it removed the video of the shooting 23 minutes after learning of it.

The company has since announced it is launching a review for reporting harmful content.

“This is something that should not have been shared around the world. Period,” Cleveland’s police chief said.

Robert Godwin Sr (Facebook via AP)

Godwin did not seem to recognise the name.

In the video, Stephens told Mr Godwin the name of his girlfriend and said: “She’s the reason that this is about to happen to you.”

Mr Godwin did not seem to recognise the name.

Investigators said that Mr Godwin was the only victim so far linked to Stephens, despite his claim on Facebook that he killed more than a dozen people.